You can fly 3D at the Arvada club in Golden. Also check out the Cherry Creek club at the reservoir. You might try Chatfield- but they don't enforce the AMA requirement too much and I found it uncomfortable. Not much frequency control or field amenities like tables and benches either.

I have a World Models 80" Extra w/G-62 and was flying it at Arvada field at 5973' altitude with a 22-10 prop at 7100RPM. It would hover at 3/4 throttle.

You can easily fly 3D with 40 size glow stuff. At 5973' it takes a .60 glow engine to hover a 5.5--6.0LB airframe at FULL THROTTLE. I had a 40 size Giles 3D that weighed 5 pounds RTF and I was running a TH .75 engine with an APC 13-5 prop and 15% fuel. It hovered at 1/2 throttle easily.

You can just barely hover a U-Can-Do 60 with a Saito 91 at that altitude, but it better be a cold morning. You won't get it to hover in the middle of the summer on a hot day. So, for extreme 3D performance on that airframe- you'd most likely need a 120-150 size engine.

It takes a HOT 50 or a decent 60 size engine (61FX or an EVO 61) to hover a TH Uproar 40 that weighs 4.5 pounds.

You can hover a H9 25% Cap 232 weighing just under 12 pounds with a ST3000. It's full throttle hovering--not much room for mistakes-- but you can do it. Prop it right. Big diameter and no more than an 8 pitch.

You can get a Sig 25% Cap 231EX to hover with a ST3000 and a 20-6 wood MA Schimitar---if you shave the weight and get it under 12 pounds. Not worth the trouble IMO. Mine weighed close to 14 pounds. Hard to lose 2 pounds on a model that size. I did it, but there's lighter stuff available today. I wouldn't buy a Sig- just to beat my head against the wall trying to get it under 12 pounds.

Generally- at 6000'--:

It takes a .60 engine to hover a 40 size plane-- better with a .70 or .80 engine
It takes a MINIMUM 1.20 engine to hover a 10 pound airframe at near full throttle
It takes a 1.80 engine to hover a 12 pound airframe at full throttle

And your DA50 turning 6800 RPM with a 22-8 won't do the trick on your 16 pound airframe-- get more cubic inches--a G-62 or a ZDZ 60 will do it just fine with a 22-10 prop around 7000-7200RPM. No substitute for more cubes.

Good luck with it.

Hope you can use that info to get yourself set up for some good 3D at 6000' elevation.